Planetary power transmissions incorporate a plurality of planetary gearsets that are disposed within a housing and subject to various thrust and torque loads. These planetary gearsets must be lubricated and sometimes cooled in order to function efficiently and properly.
The lubrication of the planetary gearsets, which are often deep within the mechanism that is covered by other components, need to have the lubrication fluid directed to their innermost surfaces so it can be fed outwardly to lubricate the gearing components.
Generally, the lubrication system in planetary transmissions is by way of an oil gallery or passage within the transmission input shaft. The oil within this passage is then fed outwardly through radially extending passages, which communicate with the central portion of the planetary gearsets. From this point, the fluid is allowed to flow radially outward as the transmission components are rotating. The lubrication does not account for the thrust loading on the planetary gearsets. During thrust loading or torque loading, the lubrication is more important and care must be taken to ensure that the parts are properly lubricated during these high level instances.